Details of multimode fibre-geometry lasers were published in the early part of the last decade (1973). By way of background, the interested reader is referred to the following articles by J.Stone and C.A.Burrus: "Neodymium -- doped silica lasers in end-pumped fibre geometry", Appl Phys Lett 23 pp 388-389 (October 1973); "Neodymium -- Doped Fibre Lasers: Room Temperature cw Operation with an Injection Laser Pump", Appl Optics 13 pp 1256-1258 (June 1974). The laser described comprised stub lengths of fibre (about 1 cm length) with core diameters ranging from 800 to 15 microns. Continuous (cw) lasing action was demonstrated using an end-coupled gallium arsenide (GaAs) injection laser as optical pumping source.
Notwithstanding considerable advances made in single-mode fibre technology, and the passage of more than a decade since that time, until now no fibre-laser fully compatible with single-mode fibre systems has been developed.